Machine for making electrode assemblies



July 19, 1949. p REED 2,476,454

MACHINE FOR MAKING ELECTRODE ASSEMBLIES Filed Feb. 10, 1949 2Sheets-Sheet 1 INVENTOR. PRICE L REED July 19, 1949. P. L. REED2,476,454

MACHINE FOR MAKING ELECTRODE ASSEMBLIES Filed Feb. 10, 1949 2Sheets-Sheet 2 INVENTOR. PRICE L. REED ATTORNE S.

Patented July 19, 1949 MACHINE FOR MAKING ELECTRODE ASSEMBLIES Price L.Reed, Royersford, Pa, assignor to Superior Tube Company, Philadelphia,Pa., a corporation of Pennsylvania Application February 10, 1949, SerialNo. 75,578

6 Giaims.

This invention relates to the manufacture of cathodes for thermionictubes and has particular reference to the disc type of cathode which isused in various cathode ray tubes, television pick-up tubes, and tubesof so-called lighthouse construction.

In tubes of the type just mentioned the thermionic emission is obtainedfrom a relatively small, cup-shaped disc coated with alkaline earthoxides. The disc must be rigidly mounted'within the tube a fewthousandths of an inch from a grid member and in accurate planealignment therewith. The disc is supported by a metal tubular memberwhich may be of any of the conventional forms, i. e., seamless or oflockseam, welded, welded and drawn, boxed, or wrap-around ribbon type,and also serves as a means of conducting heat to the disc or cupcarrying the oxides to heat it to electron-emitting temperature. Aninsulated tungsten, molybdenum or similar wire is usually placed insidethe tube to provide sufficient heat by electrical resistance to makepossible attainment of the proper temperature.

In order to support the cathode assembly ceramic or similar heatresistant insulators are employed. These insulators, generally in theform of a flat disc, are mounted on the tubular member prior to theattachment of the cup to the tubular member. The attachment of a cup tothe tubular member is generally accomplished by inserting the tubularmember into the cup which fits as a snug cap over the end of the tubeand then welding the cap to the tube.

It is an object of this invention to maintain an accurate dimensionlongitudinally between the face of the disc and the face of the capwhile welding the cap to the tube supporting the disc.

It is a further object of this invention to maintain accurate parallelplane alignment between the face of the disc and the face of the capwhile welding the cap to the tube supporting the disc.

Another object of the invention is to provide means for automaticallyrotating the disc, tube and cap assembly while making a plurality ofsuccessive welds evenly spaced around the periphery of the cap.

These and other objects of the invention will become apparent from thefollowing description read in conjunction with the accompanyingdrawings, in which:

Figure lis a perspective elevation of the apparatus involved;

Figure 2 is a vertical section of a portion of the apparatus shown inFigure 1, the section being taken through the axis of the cathodeassembly; and

Figure 3 is a vertical section taken on the plane indicated by the trace3-3 in Figure 2.

In Figure 1 there is shown a conventional bench type spot weldercomprising a support post IE3 which is mounted on a base plate I2.Moving within the support post is actuating rod 14 which extendsdownward through the base plate I2 and is coupled with a foot treadle(not shown) below the table on which the base plate rests. The upper endof the actuating rod [4 is pivotally connected to member 55, which ispivoted on pin iii. The other end of member [6 is forked and providedwith inwardly directed pins engaging the slidable upper electrodeassembly 20 within the slots 22.

When the foot treadle below the table is moved by the operator theactuating rod causes member it to rotate about pin [8 moving the upperelectrode assembly 20 downward bringing the electrode 24 into contactwith the work in a position hereinafter described in detail.

The upper electrode assembly 20 is a conventional assembly comprising aspring loading mechanism and welding current control timer initiatingswitch. These assemblies are well known to the art and need not bedescribed here.

Also mounted on the support post I!) and insulated therefrom byinsulating bushing 26 is the lower welding arm 30. Mounted in the lowerarm 36, as shown in greater detail in Figure 2, is member 32 which isrotatably mounted within the bore 34 and held against axial movement byscrews 36 and 33. Formed as part of the member 32 is a ratchet S0.Rotatably mounted on member 32 is the housing 42 to which is affixedoperating arm M. Mounted on the face of housing 42 by screws E32 iscover plate 64. Connecting link 43 connects operating arm 44 with thelever 48 which is pivotally mounted on pin i3 and is actuated by actuating rod i4 through the pin 50.

Cdntained within operating arm M is pawl 5'2 which is urged inwardly bythe action of spring 54 and engages the faces of the ratchet lobes 51,58 and 59 as will be hereinafter described.

Mounted within the member 32 and equally spaced from each other arethree pins such as are shown at 66. Each pin is backed by a springsimilar to that shown at 68 and has at its outer end a portion 61 ofreduced diameter which engages within one of three holes 69 providedtherefor in the ceramic disc member 14. Centrally mounted within themember 32 is the conducting rod is over which is placed the tube member12 supporting the disc member I4 and the cap member it, these membersforming the cathode assembly.

Also mounted on the base plate I2 is member I S on which is slidablymounted member 80 mounting a face plate 82, micrometer support plate 8 5and micrometer locking bracket 83 in which is threaded micrometerlocking screw 85. Threaded into support plate 84 is the internalmicrometer member 86 into which is threaded micrometer stem member 81which mounts the external micrometer member 88.

The upper edge of the face plate 82 must rise sufiiciently high abovethe center of the disc Hi that for any position of member 32 at leasttwo of the pins will bear on the disc below the upper edge of the plateto provide stability in order that the disc will be held in a fiatposition against the plate 82 by the action of spring load pins 66. Theplate is notched at BI to provide clearance for the tube 72 and the capI6.

Also coupled with the operating foot treadle (not shown) below the tableis a second actuating rod 98 which is connected to rod I02, through arm$32, shaft 94 and arm 98, which are pivotally supported by mountingbracket IIlEl. Pivcted on a fixed pin N34 is arm Hi6 which is yieldablyengaged by rod I02 upon motion of the rod to the left through spring I08and non-yieldably engaged by rod Hi2 upon motion of the rod to the rightthrough stop I01. The pin I Ill mounted on arm I06 engages the wall II 2of a bore within the member 89.

When the operating foot treadle is depressed the rod I4 actuates memberI6, causin the welding electrode assembly 20 to move downward and theelectrode comes into engagement with the cap member It as shown by 26'.Actuating rod it working through member 58 also actuates lever 48,connecting link 46 and actuating member M, moving member Ml in adownward direction. a In Figure 3 the pawl 52 is sliding over the outerface of a ratchet tooth while the actuating lever M and the housing 42are rotating in a counterclockwise direction, the lowermost extent oftravel of which will allow the pawl 52 to spring radially inward into. aposition of engagement below the face 59 of a ratchet tooth.

Simultaneously with this action the actuating rod 90 acting on rod I02,member I96 and pin H0. moves the member 8.9, face plate 82, and themicrometer assembly 86-, 81 and 88 to the left as viewed in Figure 2,causing the end face I2 of the micrometer rod 81 to press the cap memberIS, against the end face I23 of the member ID with a force, dependentupon the resistance to compression afforded by spring I68. The forcewith which the spring acts can be adjusted by adjusting the position ofnut I89 on the threaded portion I03 of the rod I02. Thus, the plane ofthe face of the cap. member i5 is fixed by the plane of the end. faceI24 of the rod 81.

With the apparatus in the position shown the shoulders of the pins 66are urged against the disc I4 by the action of Springs 68 therebyholding the disc member I4 fiat against the face of plate 82. It will beapparent that, by turning the external micrometer member 88, thedimension between the end face I24 of rod 81 and face of the plate 82may be adjusted to any desired value, thereby accurately establishingthe dimension between the face of the; disc member i l and the face ofthe cap member I6. When the micrometer has been adjusted to the desiredposition locking screw 85 is tightened against the micrometer 4 member88 preventing subsequent motion thereof.

When the electrode member is in its lowermost position 24 as shown inconstruction lines in Figure 2, the welding current which may besupplied by a conventional welding current timer (not shown), passesthrough lead wire II4 into conducting member H6 through flexible jumperH3, conducting member I20, electrode 24, cap I6. tubular member 12, rodIll, member 34, lower arm 3% and returns to the welding current timerthrough conductor I22. This flow of current forms a weld between thetube member I2 and the cap member I6 in a manner well known in the spotwelding art.

After the weld has been made the operator releases the foot treadleallowing actuating rod id to move downwardly thereby raising theelectrode 24 and raising connecting link 46 and operating arm as, thusrotatin the ratchet 49 in a clockwise direction, as viewed in. Figure 3,and thereby rotating the member 34, the pins 56 and the tube, disc andcap assembly through 9l to a position preparatory to making the nextweld. When actuating rod I moves downwardly actuating rod st also movesdownwardly thereby moving the rod I92 to the right allowing spring I88to expand partially relieving the pressure applied on the cap member I6between end faces lie an :23 of the rods 81 while the tube, disc and capassembly rotate as a result of the operation of the cam G6. I

When the foot treadle is depressed for the next welding operation andthe ratchet pawl 52 slides over the next successive ratchet tooth thememher 32 is restrained from rotating by the fricticn resulting from theremaining contact pressure existing between the ends of rods 81 and itand between the disc 74 and theplate. 82.

In my copendin application, Serial No. 75,527, filed Feb. 10, 1949,there is disclosed a method and apparatus for mounting the disc 74" onthe, tube l2 by forming beads in the tube, on each side. of the disc.

In the copending application of Thomas. H. Briggs, J12, Serial No.75,845,, February ll, 1949, there is disclosed a-methodandapparatus forstriking the beads, closing the beads. and1causing them to bear flatlyagainst the disc as'shown in the present application.

It is diificult to maintain the extreme, degree of accuracy of dimensionrequired between the face of the cap member leand; the face of the discmember It by relying on providing the proper length of tubing 12extending. beyond the face of the disc. This problem is further com?plicated by the inconsistencies occurring in the bend radius obtained inthe manufacture or a drawn cap such as member It. The present inventionprovides means for assembling the cap to the tube with the high degr e faccuracy required since neither the length of the tube nor thedimensions of the cap determine-the final central spacing of the face ithe insulating disc from the face of the cap.

When the foot treadle is released to an. extreme forward position theactuating rod 90, operating through arm as, shaft 94, arm 98, rod Hi2,stop 5537, member its. and pin HG, causes the member 88 to move to theright to av position entirely clear or the rod it and the electrode 24,thereby providing the necessary clearance required by the operator toinsert the assembly for welding The operator having manually pressed capit over the end of the, tube of a'tube and disc assembly slides the tubeover-the rod III and rotates the tube and disc assembly to a positionwhere the ends of the pins 66 drop into the holes 69 in the disc.

As the operator then depresses the foot treadle the member 80 moves tothe left carrying with it the face plate 82 and micrometer member 81.When the face plate 82 engages the ceramic disc the disc and tubeassembly are carried to the left forcing the pins 55 into member 32compressing the springs 68. The spring loaded pins 66 hold the disc (ina fiat position) against the plate 82. The disc and tube will be movedto the left over member 10 until the cap 18 is firmly engaged betweenthe ends of member 10 and member 81. When this position has beenattained the tube 12 will generally have been withdrawn slightly fromthe original extreme position, in which it was assembled by theoperator, within cap 16 before motion of the plate 82 is arrested as aresult of the rods 10 and 81 contacting the opposite faces of disc 16.Thus there is established the parallel relation required between theplanes of the faces of cap 16 and disc 14 in accordance with theparallel relation existing between the plate 82 and the end faces ofrods 10' and 81 and the longitudinal dimension between these plane facesas determined by the longitudinal dimension between the plate 82 and theend of rod 81 which is accurately adjusted by the micrometer setting.Further motion of the foot treadle will cause the upper electrode tomove downwardly and bear upon the cap in the position shown at 24 andinitiate a welding current impulse thereby forming a weld between cap 16and the tube 12 in the location at which the electrode contacts the cap.When the welding current flow is completed the operator will release thefoot treadle, raising the electrode from the cap, raising the operatingarm 44 and operating the ratchet to cause a 90 revolution of the member32 of the tube, disc and cap assembly as has been hereinbefore reviewed.

The operator will operate the foot treadle four times producing fourwelds spaced around the cap and will then release the treadle to anextreme forward position, again moving member 38 to the right to aposition providing the clearance required for the removal of the weldedassembly and the insertion of an assembly to be welded.

What I claim and desire to protect by Letters Patent is:

1. Apparatus for welding a member to a tube in accurate axialrelationship to an element mounted on said tube comprising an elongatedsupport on which said tube and element mounted thereon and said membermay be mounted, a welding electrode movable transversely to the axis ofsaid support, gauging means engageable with said element and with saidmember to fix their axial relationship, and means for bringing saidelectrode into contact with said member to effect welding thereof tosaid tube.

2. Apparatus for welding a member to a tube in accurate axialrelationship to an element mounted on said tube with planes of saidmember and element accurately parallel comprising an elongated supporton which said tube and element mounted thereon and said member may bemounted, a welding electrode movable transversely to the axis of saidsupport, gauging means engageable with said element and with said memberto fix their axial relationship, and means for bringing said electrodeinto contact with said member to effect welding thereof to said tube.

3. Apparatus for welding a member to a tube in accurate axialrelationship to an element mounted on said tube comprising an elongatedsupport on whichsaid tube and element mounted thereon and said membermay be mounted, a welding electrode movable transversely to the axis ofsaid support, gauging means engageable with said element and with saidmember to fix their axial relationship, means for bringing saidelectrode into contact with said member to effect welding thereof tosaid tube, and means for rotating said tube and member to successivewelding positions with respect to said electrode.

4. Apparatus for welding a member to a tube in accurate axialrelationship to an element mounted on said tube comprising an elongatedsupport on which said tube and element mounted thereon and said membermay be mounted, a welding electrode movable transversely to the axis ofsaid support, gauging means including a fixed member and an adjustablemember, said members having parallel surfaces, one of said surfacesbeing engageable with said element and the other being engageable withsaid member to fix their axial relationship, and means for bringing saidelectrode into contact with said member to effect welding thereof tosaid tube.

5. Apparatus for welding a member to a tube in accurate axialrelationship to an element mounted on said tube with planes of saidmember and element accurately parallel comprising an elongated supporton which said tube and element mounted thereon and said member may bemounted, a welding electrode movable transversely to the axis of saidsupport, gauging means including a fixed member and an adjustablemember, said members having parallel surfaces, one of said surfacesbeing engageable with said element and the other being engageable withsaid member to fix their axial relationship, and means for bringing saidelectrode into contact with said member to effect welding thereof tosaid tube.

6. Apparatus for welding a member to a tube in accurate axialrelationship to an element mounted on said tube comprising an elongatedsupport on which said tube and element mounted thereon and said membermay be mounted, a welding electrode movable transversely to the axis ofsaid support, gauging means including a fixed member and an adjustablemember, said members having parallel surfaces, one of said surfacesbeing engageable with said element and the other being engageable withsaid member to fix their axial relationship, means for bringing saidelectrode into contact with said member to effect welding thereof tosaid tube, and means for rotating said tube and member to successivewelding positions with respect to said electrode.

PRICE L. REED.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,008,628 Brown Nov. 14, 19111,703,588 Meadowcraft Feb. 26, 1929 2,393,719 Stull Jan. 29, 19462,451,169 May et a1 Oct. 12, 1948

